Tucked in a jungle of massive oak trees near sprawling rice fields in Colusa County, wood ducks have a thriving nesting area, courtesy of the California Waterfowl Association.
The association, celebrating the 25th anniversary of duck conservation efforts, is a statewide nonprofit association that aims to preserve waterfowl, wetlands and hunting traditions through education, conservation and legislative efforts. Since 1991, the group has aided in the hatching of more than 750,000 ducklings statewide. The association has more than 600 volunteers and about 600 species to observe.
Caroline Brady, CWA waterfowl programs coordinator, assists in monitoring areas of Northern California along with fellow biologist Brian Huber. The team checks about 165 of the wooden nests at Murdock Gun Club in Colusa County every three weeks, as part of the California Wood Duck Program.
“The hunters feel it’s a way to give back,” Brady said.
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During a span of a few days, the boxes are checked, eggs and hatchlings are counted and monitored. For new laying hens, a tiny metal band with a number unique to the bird is placed around its leg. The birds are researched and observed during a lifespan of three to four years, although some can live up to 12 years, Brady said.
Despite many years of research, there are still some mysterious waterfowl characteristics, Brady said. UC Davis has teamed with the group to research these, including “brood parasitism.” This happens to waterfowl when one bird lays eggs in the nest of another, Brady said.
Students at UC Davis are researching whether this type of cooperation is beneficial, Brady said.
The number of eggs a hen lays, or clutch size, ranges from nine to 12. Often, 30 eggs will be found from several hens in one nest. During the incubation period, the hen will circulate the eggs by moving them around, which can become cumbersome with so many eggs, Brady said.
John Eadie, professor and chairman of the wildlife, fish and conservation biology department, leads the UC Davis Wood Duck Project. Eadie said it is unclear if the parasitism is a communal effort or not, or if the hens are related.
The 20-year UC Davis project received a grant to fund ID chips in the last few years for four ranches that house nests.
“We’ve completely wired the populations to see what they’re doing and their survival rates,” Eadie said.
The group has chipped and genotyped about 1,500 birds a year in Northern California, Eadie said.
“These populations are somewhat distinct. Each of the subpopulations seem to be isolated; there’s not a lot of movement between populations,” Eadie said. There are genetic differences between populations, including egg and duckling size, Eadie said.
Even the West Coast and East Coast wood duck populations are genetically distinct, Eadie said.
“It’s almost a different race,” he said. “We don’t know half as much as we thought we did.”
Eadie said the California Waterfowl Association and the UC Davis programs are very beneficial.
“There is a lot of value to these programs,” he said. “They play an important role to keep populations going.”
Jessica Hice: 916-321-1550, @jesserpea